Sleeper: Good for you! Now make that boundary stick.
It took me a while to figure it out. My ex and I could NOT talk on the phone or in person. It always escalated into something awful. I finally stopped taking his calls. He refused to email. So, for a while - I sent letters in sealed envelopes and had D give them to him (which wasn't so great either). Finally about 18 months ago when our son was critically ill, I had him text for info and things improved. Now if he texts my son's workers (instead of me) - I have them reply that they are not able to make decisions about visitation or give info. FINALLY he has realized he must text me. The custodial parent. A month ago he texted me that he really needed to talk to me and asked me to phone him. I was reluctant (but did). I told him at the start that normally I do not like phone conversations with him as we don't have a good track record but that I was making an exception at his request and converse as long as he stuck to the points. He did and it was accomplished.